Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/14—Closures
  • B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
  • B22D41/18—Stopper-rods therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/14—Closures
  • B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
  • B22D41/18—Stopper-rods therefor
  • B22D41/186—Stopper-rods therefor with means for injecting a fluid into the melt
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/14—Closures
  • B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening

Definitions

• Stopper rod for delivering gas into a molten metal.
• This invention relates to a mono-block stopper rod used to control the flow of molten metal from a discharge nozzle in a holding vessel during metal teeming.
• gases injected down the stopper has been shown to have significant benefits on the quality of metal being cast.
• inert gases such as argon or nitrogen can be injected to reduce the problems due to alumina build-up and clogging or to assist in removing solidification products from the vicinity of the discharge nozzle.
• Reactive gases may also be employed when the melt composition needs modifying.
• the stopper - generally made from an alumina carbon refractory composition - is provided with an internal chamber connected to gas supply means on the one end and to a gas discharge port at the other end.
• the carbon present in the composition constituting the stopper body could reduce some of the metal oxides also present in the composition; this reduction is accompanied by the generation of carbon monoxide.
• the carbon monoxide injected into the molten metal will in turn oxidize the aluminum which has been added to calm the steel producing thereby important quantities of alumina contributing thus to the alumina build-up and clogging.
• a stopper rod adapted to deliver gas during pouring of molten metal comprising a stopper body having an internal chamber and a gas discharge port, a bore connecting the internal chamber to the gas discharge port, the internal chamber and the bore defining a gas passageway.
• the walls of the gas passageway are provided with a layer of a material which will not produce carbon monoxide at the temperature of use.
• the layer can be formed as a coating applied on the walls of the gas passageway after the manufacture of the stopper rod.
• a coating can be applied by spraying a liquid, wet or semi-wet composition or simply by filling the inner chamber with the appropriate composition. Once the coating is dried, the stopper rod can then be cured. Alternatively, the curing of the stopper can take place before the coating step.
• the layer is a liner pressed simultaneously with the stopper rod body. In this case, it is indeed possible to reduce the number of manufacturing steps.
• the layer extends through essentially the whoje thickness of the walls of the gas passageway.
• the material constituting the a layer which will not produce carbon monoxide at the temperature of use can be selected from three different categories of materials: a) materials which do not contain carbon; b) materials essentially constituted of non reducible refractory oxides; or c) materials comprising elements which will react with the generated carbon monoxide.
• the selected material will present two or three of the above properties.
• suitable material of the first category are silica (for example vitreous silica), alumina, mullite or magnesia based material (spinel).
• silica for example vitreous silica
• alumina for example alumina
• mullite for example mullite
• magnesia based material spinel
• these materials can however be somehow difficult to apply as a liner or coating (the lack of carbon in the layer can cause some thermal shock problems) and do not constitute the preferred embodiment of the invention.
• Suitable materials of the second category are for example pure alumina carbon compositions.
• these compositions should contain very low amount of silica or of conventional impurities which are usually found in silica (sodium or potassium oxide).
• the silica and its conventional impurities should be kept under 2 wt. %, preferably under 1 wt. %.
• Suitable materials of the third category comprises for example free metal able to combine with carbon monoxide to form a metal oxide and free carbon. Silicon and aluminum are suitable for this application. These materials can also or alternatively comprise carbides or nitrides able to react with carbon monoxide (for example silicon or boron carbides). [0014] Preferably the selected material will belong to the second or third categories, even preferably, it will belong to the second and third category.
• a suitable material constituting the layer which will not produce carbon monoxide at the temperature of use can comprise 60 to 88 wt. % of alumina, 10 to 20 wt. % graphite and 2 to 10 wt. % of silicon carbide.
• Such a material is essentially constituted of non-oxides species or non- reducible oxides and comprises silicon carbide which can react with the carbon monoxide if some is generated in working condition.
• Fig. 1 shows a cross-section of a stopper rod according to the invention.
• Reference 1 depicts respectively the internal chamber and a gas discharge port of the stopper rod.
• a bore 3 connects the internal chamber 1 to the gas discharge port 2.
• the bore 3 and the internal chamber 1 define a passageway for the gas.
• Fig. 1 represents an embodiment wherein the layer 4 has been copressed as a liner with the stopper body.
• the liner 4 can be constituted of several pre-formed tubular portions (41 , 42, 43) which are all copressed with the stopper body.
• a portion of the metal rod 5 connecting the stopper rod to the rigging device (not shown) is depicted in working position.
• the metal rod 5 extends beyond the highest point of the layer 4.
• a sealing gasket 6 is inserted around the lower end of the metal rod 5.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Furnace Charging Or Discharging (AREA)
• Continuous Casting (AREA)
• Furnace Details (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Manufacture And Refinement Of Metals (AREA)

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Applications Claiming Priority (2)

Publications (2)

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Cited By (3)

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Citations (10)

Family Cites Families (9)

• 2005
  • 2005-07-15 RU RU2007100205/02A patent/RU2375150C2/ru not_active IP Right Cessation
  • 2005-07-15 WO PCT/BE2005/000116 patent/WO2006007672A2/en active IP Right Grant
  • 2005-07-15 UA UAA200701790A patent/UA89642C2/ru unknown
  • 2005-07-15 DE DE602005003968T patent/DE602005003968T2/de active Active
  • 2005-07-15 BR BRPI0513258A patent/BRPI0513258B1/pt not_active IP Right Cessation
  • 2005-07-15 MX MX2007000764A patent/MX2007000764A/es active IP Right Grant
  • 2005-07-15 AT AT05763960T patent/ATE381402T1/de active
  • 2005-07-15 ES ES05763960T patent/ES2299056T3/es active Active
  • 2005-07-15 KR KR1020077001592A patent/KR101128610B1/ko not_active IP Right Cessation
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  • 2005-07-15 PL PL05763960T patent/PL1789220T3/pl unknown
  • 2005-07-15 US US11/630,633 patent/US20070210494A1/en not_active Abandoned
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  • 2005-07-15 AU AU2005263118A patent/AU2005263118B2/en not_active Ceased
  • 2005-07-15 CN CNA2005800244202A patent/CN1988972A/zh active Pending
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  • 2005-07-19 AR ARP050102974A patent/AR050257A1/es not_active Application Discontinuation
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Patent Citations (10)

Non-Patent Citations (2)

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